In order to maintain the health and welfare of milk producing animals, as well as their milk, it is very important that their udders and teats are kept clean and healthy. In particular, the bacteria that cause mastitis infections must not be allowed to proliferate and contaminate the milk harvesting equipment, thus risking the transfer of pathogens from animal to animal. To guard against this problem it is well known to treat the teats of animals with a liquid, such as a liquid disinfectant or a washing solution, either immediately before and/or immediately after milking. In the case of a pre-milking treatment application the aim is primarily to remove foreign matter and kill the bacteria present on the outside of the teat before milking. In the case of a post-milking treatment, it has been found beneficial to apply a sanitising solution and in some instances also a barrier liquid to provide a protective film that remains on the teat for some time and that seals and protects the teat end from mastitis causing bacteria. To ensure that such treatments are effective at controlling the bacteria, it is crucial that each teat is entirely coated with the liquid, and this requires the dairyman to maintain a high level of skill whilst operating the treatment process; unfortunately, for some methods of treatment this becomes arduous, especially in cases where the animal herd size is large.
In the prior art, spray bottles using a simple pump and trigger have been employed, as have more sophisticated systems such as those using vacuum operated automated spray devices, pumped spray delivery systems and back-pack spray type devices using a piston-type squeeze gun. In the latter two cases, the operator can vary the amount of liquid being applied and manually direct it to the udder and its depending teats. It is also known to treat teats with a liquid by dipping them into a rigid cup, commonly known as a “dip cup”, filled with the liquid.
The term “dip cup” as used herein shall refer to the cup-shaped component of the application device that, in use, contains an amount of treatment liquid into which a teat is dipped. Commercially known dip cups, are made in one of two forms. Either they are made as a one-part component, for example machined from a single block of material, or they are made as a two-part component, having an inner cup shaped portion that is surrounded by an outer casing. The present invention encompasses both forms of dip cup, and because of this, the term “cup portion” as used herein, refers to the single-part component as a whole, as well as to the inner cup portion of the two-part component.
The dip cup method involves the use of an application device having a dip cup which is (in the case of the single-part component) or has (in the case of a two-part component) a cup portion with an open top end that extends along a body to a closed bottom end, that is partially filled with treatment liquid supplied from a reservoir source. This reservoir source may be remote from the dip cup, in which case the application device typically comprises a handheld wand or lance, one end of which is connected to the dip cup. The treatment liquid is conveyed from the remote source through a fluid flow tube associated with the wand or lance and into the cup portion. Alternatively, the reservoir source may be a rigid container that is connected with the closed bottom end of the cup portion. In both cases the liquid may be conveyed from the reservoir source using for example a vacuum-operated pump, a peristaltic pump, a stirrup pump or using compressed air. Any of the pumps used with the application device may be manually or electrically operated. Further alternatively, a flexible squeeze container that is connected to the bottom end of the dip cup may provide the reservoir source. In this latter case, when treatment liquid is required in the cup portion, the flexible squeeze container is manually squeezed and a supply of the treatment liquid is conveyed along a fluid flow tube to an outlet located within the cup portion. In this arrangement, the outlet is often located above the desired level of treatment liquid so that air (and not treatment liquid) is then sucked back along the fluid flow tube when the squeeze on the reservoir container is released.
To operate the dip cup method, the dairy farmer simply needs to introduce an appropriate quantity of treatment liquid into the cup portion of the dip cup using one of the above techniques and then position the filled dip cup under an animal's teat, raise the dip cup up to submerge the teat in the treatment liquid contained within the cup portion, then lower the dip cup and remove it from under the teat. This operation may be repeated on as many teats as required, and the amount of treatment liquid may be replenished to maintain the appropriate quantity in the cup portion of the dip cup.
As would be expected, when the teat is submerged, a portion of the treatment liquid is displaced, causing the level of liquid to rise within the cup portion. Clearly, if too much treatment liquid is used, it will be displaced so that it overflows out of the open top end of the dip cup. However, it is important that the level of liquid is sufficient to enable the whole of the teat to be submerged in the treatment liquid. Thus it is known to provide a dip cup whose cup portion has a full circumferential extension of the portion of its body adjacent to its open top end, to form wider ring-shaped portion adjacent the top open end of the cup portion. This wider ring effectively acts as an overflow area into which teat treatment liquid is displaced when the animal's teat enters the dip cup. If the cup portion is overfilled, and more chemical is dispensed than is required, the surplus chemical moves up into this wider ring area and the dip cup is prevented from overflowing.
European Patent 0 869 748 B1 discloses an alternative manually held apparatus that again includes a dip cup which contains an amount of a treatment liquid into which an animal teat is inserted. The characterising feature of this prior art is that this dip cup has an upper overflow chamber that includes a tapered conical wall for guiding a depending teat into the dip cup. The upper overflow chamber is formed by a clipped on plastic cover that is toroidal in shape and which fits over the open end of the dip cup. This upper overflow chamber is designed to receive treatment liquid displaced from the dip cup upon insertion of a teat. A drawback with this design of dip cup, however, is that the presence of the toroidal upper overflow chamber makes it very difficult to tip out contaminated or otherwise unwanted liquid from the cup without first removing the upper overflow chamber.
Another significant disadvantage of using such an upper overflow chamber is that this design tends to make the chemical in the cup portion of the dip cup more remote from the teat than is desirable—i.e. it extends the overall height of the dip cup and this means the teat has to be inserted a long way down into the cup portion of the dip cup before it comes into contact with fluid. A further disadvantage of using this upper overflow chamber is that it needs to be dismantled from the dip cup and cleaned after each milking to guard against contamination.
Therefore, it is highly desirable to make improvements in the design of dip cup application devices, for example, to provide a device that in addition to preventing displaced liquid overflowing from the dip cup upon insertion of a teat, it enables unwanted or contaminated liquid to be tipped out of the dip cup without the need for dismantling the application device first. Further, it is desirable to provide a device that can to be cleaned without dismantling the upper overflow chamber, and also to provide a device that ensures that the dip liquid is not out of the reach of the teat being treated. These and other problems are solved by the present invention.